Loudspeakers were present on Isla Nublar to broadcast messages to park visitors and staff. Dr. Gerry Harding remarked that whenever he is crossing through the Sauropod Paddock and would find an Apatosaurus herd blocking his way, he would have the Control Room broadcast a prerecorded Tyrannosaurus rex bellow over the loudspeakers to get the herd to move. Once the island had been placed back under control during the Isla Nublar Incident, young siblings Lex and Tim Murphy discovered the recording and briefly broadcasted the roar of the young Tyrannosaurus over the loudspeakers. Hearing the noise and not realizing it was a recording, John Hammond panicked, fell down a hill, and resultingly broke his ankle. After hearing his grandchildren’s voices sounding over the loudspeakers, Hammond realized his mistake. However, before Hammond could climb all the way back up the hill, he was killed by a flock of Procompsognathus.